The v-abl oncogene of Abelson murine leukemia virus (A-MuLV) induces two opposite phenotypes in NIH3T3 cells. In the majority of cells, v-abl causes a growth arrest at the G1 phase of the cell cycle; while in a minority of cells, v-abl abrogates the requirement for growth factors. Using temperature sensitive mutants, it can be demonstrated that v-Abl tyrosine kinase is required for growth inhibition or stimulation. The two phenotypes are not caused by mutations or differences in the expression… CONTINUE READING